Methods of infiltrating high melting skeleton bodies



Marh 25,41958 'c. G. GoETzEL l-:rAL 2,828,225

METHODS oF INFILTRATING HIGH MELTING sxELEToN Booms Filed March 1, 1954 3 Sheets-Sheet 1 INVENTOR` CLA U6' Gf. GOE TZEL BY A oDIEs March 25', 19.58 c. G. GoE'r'zEL ErAL METHODS 0F INF l ILTRATING -HIGH MELTING SKELETON B Filed March l, 1954 3 Sheets-Sheet 5 QM. QN VN. NN. QN. WN

DQQ GNN.

45%@ P A N Af ATTORNEY METHODS F INFIILTRATNG HIGH MELTENG SKELETON BODIES Claus Guenter Goezel, Yonkers, and Leonard Philip Skolnick, New York, N. Y., assignors to Sintercnst Cor- 1lm'utiytm i America, Yonkers, N. Y., o corporation of ew o ` Application Maren 1,1954, Serial No. 413,258 u claims. (c1. 11T-11s).

jet-engines and the like, tools and weer resisting parts including in general articles subjected to stress-nt high temperatures and/or to corrosion, erosion-,'zibrasion, etc.

It is known to infiltrate porous skeleton bodies com` prsing Ihigh melting refractory materials, such as the ine filtration of. porous bodies of refractory metals, refractory metal alloys, or their compounds, for example tungsten carbide, titanium carbide,` etc., by contacting porous The :infiltration may be achieved by' placing the skeleton exposed portions of the skeleton body. Depending upon the nature of the surface chemistry of the materials involved, the molten infiitrant wil generally wet the skeleton body at the contact areas vand penetrate the pores until the porous skeleton body is substantially infiltrated. lf the inltrant metal s-positoncd above the skeleton body and in contact with it during infiltration the force of gravity supplements the capillary forces,t whereas if the inltrant metalis positioned below the skeleton body, the. force of gravity counteracts the capillary forces. The aforementhe production,` of iniltrated refractory carbide bodies, in particular titanium carbide, and cvenr'ixi the production of the production of infiltrated or heat vots certain grbdes of cernentedcarbides, graphiteTv/as not found to be -too satisfactory .as a supporting material and 2,828,225 Patented Mar. 25, 1958Y harmful in that it the properties of generally was IY more stable materials, for example refractory ports, but in many instances the refractory oxides were' likewise not too satisfactory actions in which gaseswould be evolved leading toA physical disruption of the skeleton, porosity, Aetc. In addition, the .final product lwould have' poor properties due to the porosity and the formation of brittle side reactions.

The presence of free carbon appeared to have an adverse elect on most refractory oxides and' supporting. materials during inlltrnto In controlling and confining the infiltration within the porous skeleton body, it was found necessary in many instances to surround substantially completely the skeleton body with a bedding support of refractory material Icaying exposed a part of the skeleton upon which the-infiltrant metal was placed. As the inltrant metal' melted',v it penetrated the porous body and was substantially conlined therein by the layer of refractory material supporting and surrounding said body. The aforementioned' method is described in copending U. S. patent application Serial No. 292,498, filed on June 9, 1952, now Patent'No'. 2.793509. In the parent application it was pointed` out that when the titanium carbide powder employed in producing infiltrated bodies contained from about 1%A to free carbon, it was difficult to obtain infiltrated conium oxide, carbide, etc., which led to unsatisfactory infiltration due to the detrimental formation of surface incrustations, surface porosity, surface adhesions, etc; The problem was further aggravated by the high infiltration tempera`v tures employed which were inthe neighborhood of 1400"4 C. or 1500 C. and higher. Bodies produced under thev foregoing adverse conditions usually were non-uniform. and had unsatisfactory strength properties;

out in the aforementioned copending case (U.

oxide, particularly substantially chemically pure alumi-y numoxide, which enabled the satisfactory infiltration of skeleton bodies made from titanium carbide powder con taining free carbon in amounts ranging from about 1% toabout 3%.

Additional work since the aforementioned develop mentv has shown that the composition oftitanium carbide is particularly critical with regard to the type of skeleton-supporting material employed in producing satisfactory infiltrated products. Thus, it was found that while aluminum oxide was an slightly in composition and had a' lower free carbon content.-for example below about 0.5%

0.2% or even about 0.1%. Generally, when the titanium carbide powder containedA less than about 1% free carbon, there was a marked tendency for the infiltrated magnesium oxide, thorium oxide, silicon" and as low as about.

'. used for the infiltration of a turbine bladesleleton in ac- 3 article to adhere, weld and stick to the aluminum oxide or become eroded which required subjecting the infiltrated article to considerable cleaning or nishing by grinding and' by -other mechanical operations Even then the cleaned articles were not always uniform and did not aln wayshave the desired strength properties or soundness,

I especially adjacent the adhering surfaces.'

- It has now been "discovered that porous titanium car- I bide skeletons produced from titanium carbide powder containing lower amounts of free carbon can be successfully infiltrated by employing another special refractory oxide skeleton-supporting material which does not substantially adversely aEcct the resulting infiltrated product.

lt is anobject of the invention to provide a method whereby titanium carbide powder containing at least about 0.1% free. carboncan be utilized in forming skeleton bodies capable of being infiltrated at elevated temperatures to form bodies requiring a ci finishing operations. f Other obects and advantages will btfcorne apparent from the following description taken in conjunction with the accompanying drawing in which:

Fig. l is a vertical sectional view along line 1--1 of Fig. 2 of a high frequency heated vacuum furnace to be coi-dance with the invention;

. Fig. 2 is avertical sectional view ou line 2--2 oE'Fig. l; Fig. 3 is a vertical sectional view of a 'high frequency 'vacuum Ifurnace for the infiltration of a' plurality ol preferably above B00" C. of a porous skeleton body produced from titanium carbide powder having a free carbon contentlof at least about0.l%l wherein a refractory bedding'or support material comprising a substan-l port the 'skeleton' during infiltration. It has been dis-A covered that when the aforementioned type of skeleton.v supporting material is employed, infiltrated titanium base j carbide bodies of unexptedly improvedphy'sical propertiescan be obtained by employingtitanium carbide o powder containing free carbonio lower amounts than was i heretofore usable with alumina supports. In addition the infiltrated are characterized by improved.` surface' cleanliness, good shape retentionand' are not prone -to stick to or react substantially dctrimentally with the skele- 65 tomsupporting, berylliabase,.refractory material.' The skeleton-supporting material has been folm'd particularly satisfactory inthe production of infiltratedtitanlunt carbide bodies wherein 'the titanium carbide powder 'emprayed if. making the badyeonmns atresstabourum 70 free carbon and ranges up to about 1%'.

: In carryingrthe inventionjint'o j'practice, is preferred that aberylla-ba'se refractory material comprising sub'- stantially chemically-pure beryllium oxide powder-be eniploycdas' the-'skeleton-supporting material. One grade'of 75 escenas berylla which has given good results is a chemically pure grade having a beryllium oxide (BeO) content of atleast about 99.5% with the balance incidental impurities such as iron oxide, aluminum oxide, lead oxide, etc. A chemically pure grade of'beryllia which has givenparticularly good results is oni-containing about 99.8% of beryllium oxide. Generally, satisiactoryresults are obtained when the skeleton-supporting berylIia-base material has a beryllium oxide content of at least about 85%. rthus, the berylliabase material may contain other refractory materials, for example, up to about calcium oxide, up to about 10% aluminum oxide, up toabout 10% magnesium oxide, up to about 10% thorium oxide, up to about 10% zirconium oxide, up 'to about 5% silicon carbide, up to about 2.5% silica, up to about 2.5% boron carbide, etc., vthe total amounts of the other refractory materials not exceeding about of the beryllia-base material. Itis, however, preferred that' the beryllium oxide content be in excess of about 97.5% and thus be considered as substantially chemically pure for the purposes of the invention;

The beryllia-base, skeleton-supporting material may be employed either as a loosely bedded powder, as a coating on a refractory support, in a vcompacted and sintered tially .stable bcryllia-base material is employedl to sup.-

form, or a hot pressed or slip cast form. In hot pressing flat support plates of beryllia, beryllium oxide powder having a'theoretical density of about 3.0 l6 grams per cubic centimeter ispressed in a graphite mold to a volume corresponding to an apparent density of atA least about one gram per cubic centimeter at a pressure of at least 0.5 t. s. i. (tons per square inch) at a temperature of about 1500u C. to 2000 C., for examp1e,`by pressing at about 2 t. s. i. to about 2.3 grains per cubic centimeter at about 1700 C. for about 10 minutes. The pressed beryllia plate is cooled in and then removed from the mold and fired nair at about l000"C. to remove the carbon adhering to it fromlbc mold walls. Beryllia plates produced in the manner given in the aforementioned example are quite tough and can be dropped onto a cement floor without substantially fracturing or being otherwise destroyed. vSuch plates have been found very satisfactory as -sleleton'supporting material vin producing a ring-shaped, wear resisting part by the infiltration of a porous ring blank produced from titanium carbide powder containing at leastabout 0.1% free carbon.

As has been stated hereinbefore, the present invention -is particularly applicable to the utilization 'of titanium carbide powder containing free carbon ranging from about.0.1% to about l% in the production of infiltrated bodies having improved' strength properties at elevated temperatures. In producing such bodies, a titanium-base carbide powder may -be employed containing by weight up to 20% -tlmgsten carbide, up to 10% chromium carbide, upto 10% tantalum carbide and up to 10% Acolumbium carbide and/or a combination thereof. By titanium-base carbide is meant a carbide comprising substantially titanium carbide yund includes ttanilmicarbide per Generally, the titanium carbide powder contains at least about-74% titanium and atotal carbon content of-at least.17%, the freecarbon content being at least about 0.1%.v The balance of the titanium carbide powder may comprise on'eor more of the elements ironyzirconium, alunrinumfsilicon, chromium, manganese, magnesium, molybdenum, tungsten, columbum, tantalum, calcium, vanadium, copper, barium, strontiumysodium, as well as hydrogen, oxygen and nitrogen, etc.,l in .amounts which do'not adversely atleet the use of the powder in the process..

'The titanium carbide skeletoli 'employed'inthe infiltration process may be produced either by' cold pressing` followed by sintering or directly by hot pressngtitanium A carbide powder mixed with about 5% to 20% by weight of at lea'st one binder metal selected from the group consisting of nickel, cobalt, and iron. Generally, the porous Aslueletonfbody will have a pore volume ranging from senses about the skeleton being about 80% pore volume should range from to 45% by valine for the factory being of the order Voi. about 35% to.-r40% by volume (65% to 6(l% by volume for the skeleton). In producing the skeleton by of titanium carbide powder and the binder metal mixed therewithV is cold p ressedto a predetermined volume sutcient to produce a skeleton of about 40% when `the cold Sutered lat sub-atmospheric pressure, usually in a vac uum st an elevated temperature, e.- g., at about 1400 5 toy 60% voids.wih the volume oeenpled by 'to' 40%.?y Preesbly, the about to 55% (75% skeleton), the most satistiall'y chemically pure beryllx'a of at least 97.5% BeO conf nfltrantlmetal alloy placed on top of the assembly is then heated in a carbon tube vacuum induction furnace to an elevatedtemperature, for instance 1400 C., for va time suitable to eiect complete iniltration, the vacuum being maintained at less the skeleton tends to lose its and adhere to the It 1s essential that the infiltration be carried out in u controlled, non-oxidizing atmosphere of subatmospheric pressure, i. e., in a technical -vcuum of less than 500 microns down to about microns or lower of me cuxy column, preferably at a tempeature of at least that of the temperature subsequently employed during the nfiltration and having a pore volume'A pressed skeleton body is Fig. 2, vessel 2 rests with both of its sides contacting the graphite tube 13.

Figs. 3 and 4 illustrate a vertical vacuum furnace suitable for infiltration of a group of blades. water-cooled vacuum tight illustrate the arrangement of the iniltration vessels 2. The skeleton body 1 of a turbine blade comprising a free-carbon containi g grade of titanium carbide is positioned in vessel 2 and a pack support or bedding 3 of substantially chemically pure bezyllium ox- The inltrant metal may beatresistant nickel-base alloy. While the comprise a foregoing such as tools, wear articles subjected in use to corrosion,

with or without othe elements employed as strengtheners, h as titanium, zirconium, Examples of heat resistant alloys which have been found satisfactory ferial, there are several alternative ways in which it canv be -For example, 'itcan be painted in.the form of'azliquid slurry onto -another ceramic orgraphite supportnd heat treated to produce an adherent coat. When employing alliquid slurry of beryllia in producing a coated support, it is preferred'that a fused grade of beryllia of high apparent density beused las' this type of beryllia forms a more uniform. coating on a supporting refractory` type base.A .0f course, precautions must be-talcen against cracking of the coatingI durnguse, otherwise the iniltrant metal willY react detrimentally with thunderlyng base material with the result that'iuferior Ainfiltrated articles will'beprodueed. l n

l, Flat beryllia plates can` be produced by hot pressing `8 carbon levels, superior properties areiindcated vvhen berylliafis employed as a .support material. It will be noted'from Fig. l1' that in the regiorit'vhere theberyllia atjlovvertempcraturesby the addition of a small amount of lime. LIhus, less than 1% of lime will lower the hot pressing temperature to as low as 1500 C. Up to 10% by weight of lime (CaO) may be mixed with chemically pure beryllia for this purpose and still g'ive satisfactory results when the `support is employed in the intlration of titaniutncar'bide skeletons containing less than about` 1% lfree carbon. Other additives which may be used 'for 'lowering the hot pressing temperature aro alkall metal oxides and tluorides, or silica, or magnesium silicate.

` As has been pointed out hereinbefore, beryllia is particularly supcriorin itsbehavior as a skeleton-supporting material for.. tifaniumf carbide skeletons produced from.

titanium carbide powder containing free carbon in amounts up toabout 1%. When the free carbon content of the titanium carbide powder substantially exceeds 1%, inferior and erraticproperties of the finally inltratcd article are indicatedwhile below about 1% free carbon, the .properties are markedly improved and more consistent, particularly below 0.5% free carbon., This is brought out clearly by the three bands of curves of Fig. 1l which illustrate the effect of the support material on the modulus ofrupture properties atlroom tempcramxe when titanium carbide skeletons produced from titanium icarbide powder containingA 4free carbon in amounts rang-v ing from aboutl 0.1% `tti-about 3% are infiltrated with a heat resistant nickel-base alloy while supported by isubstantially chemically pure-beryllia, bysubstantially chem'- .ically pure alumina and by graphite, respectively. All skeletons were inliltratecl at a temperature in the neigh borhood of about 1400 C. and comprised about 60% to 65% by4 volume of. titanium carbide in the final prodwItvvvill be noted tromthefbahnds of Fig.- 1l that infiltrated'titahiuin' carbide bodies of satisfactory properties are obtained. withfberyllia-as a vsupportwheu the free carbon content of-titanium carbide isbelovv about 1%, particularly beloivA 0.5%, while above about 1% the propand alumina bands cross below and above. the area near 1% free earbomthat is fromv about 0.6% or 0.7% to about`.1.2% carbon.' comparable and .satisfactory properties when either berylla or alumina are employed as skeletonsupporting materials. Graphite, on Athe other-'hand indicated inferior results over a wide rangeof free carbon content up to 3% free carbon, 'the maximum vmodulus ofI rupture hardly reaching 130,000 p. s. i. with minimum values falling to below 80,000 p s. i.; anti-evento below 40,000 p. s. i. Generally speaking, a minimum` room temperature modulus of rupturc of atleast about 140,000 p. s. i. as obtainable when beryllia is 'employed as a support for free carbon contents ranging from about 0.1% Yto about 1%, is destrable.

Aztmlogcuis etects were also observed when titanium carbide skeletons were infiltrated with cobalt-base heat resistant alloys. Y

Similar trendswere also indicated for modulus of rupture properties determined at l000 C.l A skeleton body produced fromtitanium carbide powder containing about 0.2% free carbon and infiltrated while in contact withralumina exhibited a low modulus of rupture at 1000' C. of about 76,000 p. sai. ,On the other hand, a similar skelcton'body produced'from 0.2% free carbon titaniumcarbile and intltratedwhile in contact with beryllia exhibited a much higher modulus ofrupturc at 1000." C. 0f about 110,000.v p. s. L However, when beryllia was employed as a support fora titanium carbide material containing a .high free carbon content :of 2.4%, a low modulus of vrupture M1000 C. of 89,000 p. s. i. wasobtained. When aluminawas employed as a support for a titanium carbide material containing 2.53% free ertes fall ot in. rn'agnitudeand exhibit a wide range of variation.V When..alumina is employed as a support, i11- ferior propertiest linsofar tls-uniformity is concerned, are

- obtained at free carbon 'contents beiow about 1%, es pecially. below 0.5%, rvhile nbove 1% and up to 3%, or higher, markedly improved properties are obtained. This improvement at higheri free carbon levels of .titanium carbide with alumina as a support is covered-inthe eopcnding U. S. patent application Serial No;- 292,498. It will be noted from the l'baud for beryllia `in Eig. ll

that when' the titanium carbide powder in produingtlieVv skeleton contains about 0.2% ree-carbon, the beryllialf Vsupported infiltrated titanium carbide skeleton inldiiites; .toom temperature modulus of. rupture strength properties ranging from over 180,000 p.- s. to;approxmatcly 220,000 p. Vi. On the other hand, when alumina is employed Vas a'support for the same'low free-.carbon of is indicated .varying over a wider; range froxn carbon, a much higher modulus of rupture of 141,000 p. s.-i. was obtained at 1000'l C. Thus, for titanium carbide of low free carbon content (i. c. below about 1% tree carbon and especially below 0.5 berylla is superior to alumina as a support material, while at high free carbon contents (i.e. above 1%' free carbon) alumina is superior to beryllia.

A grade of titanium carbide containing about 78.3% titanium, about 19.1% -total carbon and about 0.2% free carbon gave satisfactory results as a skeleton when in' lltrated with a. nickel-base alloy (comprising 13,59% chromium, 8.28% titanium, 5.72% iron, 1.56% aluminum,t0.0 76%.silica, 0.85% carbon-and the balance essen` lially nickel) while supported by a plate of hot pressed beryllia. The modulus of rupture of a test piece at 1000* C. was approximately 110,000 p. s. j., the test picce exhibiting a high bending angle of 31 vdegrees at fracture. 'lfhc Toom temperature modulus of rupture was as high as 235.00011. sii.'

Similar bodiesinlltratedgwith an alloy containing.

93.5% nickel,V 4.3% aluminium, 0.5% silicon, 0.3% manganese, 0.3% carbon and .the balance incidental elements, utilizing beryllia'as a' support, have shown that sound products can be obtained with a modulus of rupture at 1000 C. of v116,000 p. s. i.`.V exhibiting a bending angle of l2 degrees at fracture. The modulus of rupture at room temperature was about 180,00019. s. i.

Likewisetita'uium carbide bodies produced from tira nium carbide powder containing f rec carbon of theorder of labout 0.2% when inlltrated an alloy containing about nickel and 7.5%.aluminum 'have yielded markedly improved ,modulus of'rup'turepropertics of the order` of i15,0 00 p. s. i. at .1000"A C. witha 46 degrees bending angle at fracture. The `roomtempe`ratore`modulus ofrupture', was as high as 223,000`p.- s. i. Similar re sultsjj were indicated `with nicltebb'ase alloys containing up Y better understanding of the invention, the' following add-y of erosion. The properties obtained on test sections were tional illustrative examples are given: of a markedly lower order of magnitude than the proper Example I ties o tained on test sections of the blade skeleton infiltrated while supported by beryllia. Moreover,

V'In producing aturbine blade. a batchv of titanium Cr- 5 the alumina-supported blade did not infiltrate as rapidly bide powder passing through a 32 5 mesh screen and conas the beryllia-supported skeleton. The alumina-suptainills.'lpproximately 79.1% titanium, about 19.2% comported blade skeleton took 6 hours while the beryl1iabined carbon and about 0.3% free carbon was mixed supported blade skteleton took only one hour to infiltrate with about 5% by weight of carbonyl nickel powder passadequately.

ingthrough 325 mesh. The mixture was dry milled 'in a 10 Example Il Stainless steel ball null for about twenty-'four hours. The In producing a Img shaped Wear resisting part n t tani carbide powder all passing through 325 mesh blended dry with about 1% by weight of n thermosetting "m phenolformaldehyde ype resin was than mosned wm and containing approximately 79.1% titanium, about ace/one and we? mixed thoroughly. and the powder mass 15 19.3% combined carbon andabout 0.2% free carbon was ally dried, pulverized and passed through a 100 mesh mixed with about 5.% by. wc'ghtff cobalt Powder' The ne horsat 1400. under vacuum vThe vacuum im by .weight of a thernrsetting phenolforxnaldehyde type f5 microns of mercury mma of furnace` atmsphere thoroughly and the powder mass finely dried, pulverized comprising carbon monoxide. The sintered block was and Passed thmuh a 100 mesh screen Ahoi 200 gltms cooled under lvacuum, removed and then accurately ma if the Powdf'fr mm was Compacte# 20M U1 a ifalbtd chined tothe contours of the iinshed blade shape. VThe 5 lined steel di? af a Pressure'f 4 t- S- l m0 a Cylllldl'lal total weight of the skeleton body was approximately 32() Slug abt 1 high and 2V* m dmmf @11d t0 a density grauw y of approximately 61% of full-density, i. e. to a pore fhezimaton stimmtV was pressed from a powder volume of about 39% of the total outside volume of the grade o f beryllia of the calcined type, all passing through S1ugl 325 mesh and comprising about 99.8% beryllia (BeO). The pressed cylindrical compact was sintered at 1400. The ho; pressing cf this Shape was' concluded .in an im C. for about one hour ma vacuum of 2O microns of duction heated graphite mold at atempei'ature of 1550 C. n m'cnf' Column at he en d 0f the s lnfel'l'lg Cycle. The and at a pressure of about 2 t. s.'i. for a period of about Smred 001993@ was Partially machined t0 form a blind ten minutes to a pressed density of about 1.2 grains per hoge 0l' Cflllty OQBOUPHQ roughly i0 the Cavity 0f the cubic centimeter. .Two mating beryllia pieces were 35 imshed mg Us cavity Serving as a l'eseflil fOl the pressed, onefhal of which contained the negative of the umhllt mtal- The closed bottom 0f the Cavity W35 convex Shape of um vane and the other half of which maintained in order to retain the intltrant metal. The fitted the concave side.' These ltwo pieces were' heated in` 503i Weight 0f the Skeleton after machining W38 abllt nir to remove residual surface carbon. The bladeskeleton 155 Bramswas then placed carefully between ythe two mating halves, 40 AbOUt 240 grams 0f i!v Gohan-'bam alloy (Smilie-36) -hus providing g tight Seal alongl the edges, and the enh-re was placed in the cavity of the ring blank and the skeleton assembly placed in' the horizontal position inte graphite mounted Onto s dat supporting disc 0f compacted beryllia carrier. The blade was placed Awith the concave side up. Pldlld ffOm a grade 0f POWClel'll Passing trough a Tungsten weights were used on' the upper berylli'a piece 100 mesh screen and containing about 99.5% BeO. The so as 10pm/enf my movempni, About 100 grams of uw ,L5 assembly was heated in a carbon tube vacuum furnace at in tltrant metal was placed at one end of the blade skelea temperature of about 1450 C. for about One 110111".

13.59% chromium, and balance essentiallynickel. The reaction of residual atmospheric oxygen with the carbon skeleton body with the inlllrant metal on one end ,was tube of the furnace, was evacuated during the heating and heated in` a carbon tube vacuum furnace and broughtvup the infiltration treatments. The vacuum improved from to 1300 C. and held there for about one hour.v The a sub-atmospheric pressure of about 200 microns down infiltrant metal melted andppenetrated the pores of the to a Vsub-atiziosp eric pressure of about 25 microns of c um increased, corresponding to a drop in pressure from perature under a neutral or reducing atmosphere at atabout 10U- microns to about 10 microns of mercury. mosplieric pressure.

column. 'l'he'iniltrated body was cooled in vacuum until 60 The resulting blank which contained about 61% by the nflltrant phase solidiedand the cooling Ithen convolume of titanium carbide had a weight of 404 grams drilled 0WD t0 Toom fnlieatil'C in a reducing 0f UCUUHI and a density of about 6.6 grams per cubic centimeter. atmospefefslbstmtauy amlphedc Pessufe- The Ainfiltrated ring blank separated cleanly from the The "mtfad ma@ sepu'lted from the SUPPOUS bed beryllia support and could be machined and lapped to its of be-,ryua Ver? easily, exhibited awww! and'cla sur' 65 final ring dimensions and shrink-ttted into an alloy steel face and showed good shape retention and relatively sharp casing. .l

con-1ers and edges' :me blade had an average density of- A ring similarly prepared from the same type of tia ut 6.4 ra s e cuic centimeter and we' hed ab ut 123 grantsg alli-1er premoifal' of the (,Xcss'gnmlam mal tanium carbide powder but infiltrated on a dat alumina from the end atwhih t'entered he bdy. .m support did not exhibit good surface quality and further- A similar blade produced from the slime titanium car. more adhered to and .tended to spread out on thesupport. bidepowder of 0.3%irec carbon content but inlltrated Mol'ovef ihre alumlllaSuPPQffed Skeleton did not m' While supported by had f alumina showdcd inferior re. ltrate as rapidly as the beryIlia-snpported skeleton. The suits. The surfce-o"f'the blade -was rough, had surface alumna-supported skeleton took live hours to infiltrate adhe'sioneEhad scatteredporosity and also showed *signs Vmiadeqixntely, as compared to the berylliaesupported skeleobtained'.

assenza ton which iniiltx'atedI inonly one hour to produce a markedly improved wear resisting ring.

One of the outstandingadvantages to accrue from the use of beryllia or bcrylIia-base refractory materials as binder metal at relatively high temperature, e. g. 1100 C.

to i500 C. or higher, While the beryllia-basc support is in contact with the article being sintcrcd.

Although the present invention has'been described in Y conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and vscope of the inven tion, as those Vskilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims. Y Y

What is claimed is: l. l Y

l. In a method Afor producing a hard, hatancl wear resistant, high strength titauiumlbase carbide body from a heat resistant matrix-forming metal and titanium carbide powder containing about 0.1% toA A1% free carbon, the improvement comprising forming a .bodycontaining substantially said free-carbon-containing titaniumbase carbide and heating s aid titanium carbide in the presen@ of a liquid phase of said heat vresistant matrix-forming metal at an elevated temperature above the liquidus temperature of said heat resistant metal while said' body is supported vby and in contact with a bcryllia-base support containing at least about 85% beryllium oxide.

2. In amethod for producing a hard, heat and wear resistant, high strength titanium-base carbide body from a heat resistant matrix-forming nietaland ti tanium carbide powder containing about 0.1% `to 1% free carbon, the improvement Acomprising forming a porons skeleton body of said free-@rbon-containing titaniumbase carbide powder and nltr'ating said skeleton body with a molten heat resistant intiltrant metal at a temperature above the liquidus temperature of said iniiltrant metal while said body is supportedby and in contact with a beryllia-base support containing at least about 85% berylliumoxide. i j

3. In a' method for producing a hard, heat and wear resistant, high strength titanium-base carbide body by thev infiltration of a porous, skeleton body containing substantial amounts of titanium carbide, the steps compris` contacting a portionl of said supported skelctonwith at least one matrix-forming inltrant metal selected lfrom the group consisting of nickel and cobalt, their alloys with l eachother, and heat resistant alloys 'based on atleast one metal of said group, subiectingfsaid supported skeleton lv12 c arbon, supporting said skeleton body by a beryllia-base support containing at least about 85% beryllium oxide, contacting a portion of said supported .skeleton with at least one metal from the group -consisting of nickel and cobalt, their alloys with each other, and heat resistant alloys based on at least one metal of said group, subjecting the thus-supported skeleton to infiltration at a temperature above the liquidus temper-autre of said infiltrant metal in a controlled non-oxidizing atmosphere .of subatmospheric pressure below about 500 microns of mer-v cury column, whereby the beryllisuppored skeleton body is substantially completely infiltrated and an inltrated titanium carbide body of consistently high strength properties s obtained. v

5. In a method for producing a. hard, heat-and wear resistant, high strength titanium carbide body-bythe-inltration of a porous skeleton body containing substantial amounts of titanium carbide, the steps comprising forming said porous skeleton body from titanium carbide -power containing about 0.1%-to 1% free carbon, supporting said skeleton bodywith a beryllia-base support containing at least about 8 5 beryllium oxide, contacting a portion of said supported skeleton with .at least one metal selected fromthe group consisting of nickel and cobalt, their alloyswitheachf'otlier, and heat resistant alloys based on at least one metal of said group, subjecting the thus-supported skeleton body to infiltration at a. temperature up to about 2501 C. above the liquides tempe'ratureY of said inltr'ant metal `in a controlled nonoxidizing atmosphere of sub-atmospheric pressure below about 500 microns of mercury columnfwhereby the beryllissupported skeleton 'body is substantially complctely infiltrated and an iniltrated titanium carbide` body of consistently high strength properties is obtained.

6. In a method for producing a'hard, hc'at and wear resistant, highstrength titanium carbdebody by the into infiltration at a temperature above the lquidos temperature of said inltrant metal in a controlled non-oxidizing atmosphere of sub-atmospheric pressure, whereby the bcryllia-supported porous skeleton body is substantially.

completely. inltrated and an iniltrated'titanium-base carbide body of consistently high strength properties is 4. In va method for producing a hard, heat and wear resistant, high strength titanium carbide body by 4the-' infltration of a porous'fskeleton'body containing substanpowder containing"about"OLl% tobout 1%'. ot'free filtration of a porous skeleton body containing-substan- A tial amounts of titanium carbide, the steps comprising forming said porous skeleton body from a. titanium-basc carbide comprising up to 20% tungsten carbide,.upto

10% chromium carbide, up to `10%l tantalum carbidenp to 19%V columbium carbide, substantially the balance befv ing titanium `carbide powder containing about (3.1%A to 1% free carbon, supporting said skeletonbody, with asequa-base Suppen containing at least about ery1 lium oxide, contacting a portion of said supported skele- -ton with at least one metal selected from the group consisting of nickeland cobalt. their alloys with each other, and heat resistant alloys based on atleast' one metal of;

said group, subecting the thusoupported skeleton body to infiltration af. a temperature up-to about 250 C. above the lquidos temperature of said ntltrnt metal inl a'controlled non-oxidizing atmosphere of sub-atmospheric pres prising about 40% to about 80% by volume of the body,

supporting said skeletoniwith a support consisting essentially of chemicallypure kberyllium oxide, contacting a portion of said supported skeleton with atleast one metal selected from the-group consisting of nickel and cobalt, their alloys with each other, and heat resistant alloys based on at least-one metal of said group, subjecting the thus-supported skeleton body to nlltration at a temperature up Yto about 250 above the Iiquidus temperature ofsaid nltrant metal in a controlled non-oxidizing atmosphere of subaunosphcc pressure-ranging from about 500 microns down to aboutS microns of mercury column,

where the beryllia-supported skeleton body is substantially completely infiltrated and an inltrated titanium carbide body of consistently high strength properties is obtained.

8. In a method for producing a hard, heat and wear resistant, high strength titanium carbide body by the infiltration of a porous skeleton body containing substantial amounts of titanium carbide, the steps including forming from titanium carbide powder containing about 0.1% to 1%v free carbon a porous skeleton body comprising about 40% to about 80% by volume of the body, supporting said skeleton with a beryllia-base support containing at least about 97.5% beryllium oxide, contacting a portion of said supported skeleton with at least one metal selected from the group consisting of nickel and cobalt, their alloys with each other, and heat resistant alloys based on at least one metal of said group, subjecting the thus-supported skeleton body to infiltration at a temperature up to about 250 C. above the liquidus temperature of said iniiltrant metal in a controlled nonoxidizing atmosphere of sub-atmospheric pressure ranging from about 500 microns down to about 5 microns of mercury column, whereby the beryllia-supported skeleton body is substantially completely infiltrated and an infiltrated titanium carbide body of consistently high strength properties is obtained.

9. In a method for producing a hard, heat and wear resistant, high strength titanium carbide body by the infiltration of a porous skeleton body containing substantial amounts of titanium carbide, the steps including forming from titanium carbide powder containing about 0.1% to about 0.5% free carbon a porous skeleton body comprising about 40% to about 80% by volume of the body, supporting said skeleton with a berylia-base support containing at least about 97.5 beryllium oxide, contacting a portion of said supported skeleton with at least one metal selected from the group consisting of nickel and cobalt, their alloys with each other, and heat resistant alloys based on at least one metal of said group, subjecting the thus-supported skeleton body to infiltration at a temperature up to about 25 C. above the liquidus temperature of said iniiltrant metal in a controlled non-oxidizing atmosphere of sub-atmospheric pressure ranging from about 500 microns down to about 5 microns of mercury column, whereby the berylliasupported skeleton body is substantially completely iniiltrated and an infiltrated titanium carbide body of consistentlyA high strength properties is obtained.

10. In a method for producing a hard, heat and wear skeleton with at 250 C. above the liquidus temperature of said inltrant metal in a controlled non-oxidizing atmosphere `of sub-atmospheric pressure ranging from about 500 microns down to about 5 microns of mercury column, whereby the berylliafiltrated and an infiltrated titanium carbide sistently high strength properties is obtained.

l1. In a method for producing a hard, heat and wear resistant, high strength titanium carbide body by the infiltration of a porous skeleton body containing substantial amounts of titanium carbide, the steps including forming from titanium carbide powder containing about 0.1% to 0.5% free carbon a porous skeleton body comprising about to about 65% by volume of the body, supporting said skeleton with a beryllia-base support containing at least about 99.5% beryllium oxide, contacting a portion of said supported skeleton with at least one metal selected from the group consisting of nickel and cobalt, their alloys with each other, and heat resistant alloys based on at least one metal of said group, subjecting the thus-supported skeleton body to infiltration at a temperature up to about 250 liquidus temperature of said intiltrant metal in a controlled non-oxidizing atmosphere of sub-atmospheric pressure ranging from about 500 microns down to about 5 microns of mercury column, whereby the berylliasupported skeleton body is substantially completely inliltrated and an infiltrated titanium carbide body of consistently high strength properties is obtained.

References Cited n the tile of this patent UNITED STATES PATENTS 

1. IN A METHOD FOR PRODUCING A HARD, HEAT AND WEAR RESISTANT, HIGH STRENGTH TITANIUM-BASE CARBIDE BODY FROM A HEAT RESISTANT MATRIX-FORMING METAL AND TITANIUM CARBIDE POWDER CONTAINING ABOUT 0.1% TO 1% FREE CARBON, THE IMPROVEMENT COMPRISING FORMING A BODY CONTAINING SUSBSTANTIALLY SAID FREE-CARBON-CONTAINING TITANIUM-BASE CARBIDE AND HEATING SAID TITANIUM CARBIDE IN THE PRESENCE OF A LIQUID PHASE OF SAID HEAT RSISTANT MATRIX-FORMING METAL AT AN ELEVATED TEMPERATURE ABOVE THE LIQUIDUS TEMPERATURE OF SAID HEAT RESISTANT METAL WHILE SAID BODY IS SUPPORTED BY AND IN CONTACT WITH A BERYLLIA-BASE SUPPORT CONTAINING AT LEAST ABOUT 85% BERYLLIUM OXIDE. 